a) Technical Field of the Invention
The invention is directed to a process for the production of solid magnet bodies from materials with soft magnetic properties using the method of die casting. The process is applicable for the production of soft magnetic magnet bodies for relays, transformers, magnet valves, actuators, and other electromagnetic products.
b) Description of the Related Art
It is already known to produce solid, soft magnetic magnet bodies by powder-metallurgical methods. In doing so, however, it is very complicated and often impossible to prevent pores in the finished articles. Pores, which are the source of internal shear, as it is called, cause extensive deterioration of the soft magnetic characteristics of high-grade materials. Powder-metallurgical methods are accordingly suitable for the manufacture of solid, soft magnetic magnet bodies only conditionally.
It is also known to produce solid, soft magnetic magnet bodies for electric machines using the precision casting method (DD 108 628). For this purpose, a mold must be produced for every individual cast article and must be removed from the cast article after casting in a laborious manner using aggressive auxiliary materials which generates waste. The precision casting method is therefore uneconomical for mass manufacture.
It is also already known to produce solid, soft magnetic magnet bodies for electric machines by the die casting method (DD 126 155). The die casting process which enables high productivity in principle has so far not been successful in practice for the production of solid, soft magnetic magnet bodies because, as a result of the high melting point of typical soft magnetic alloys, the die casting tools a very short life and manufacturing is accordingly uneconomical. Changing the alloy composition is impossible because of the deterioration of the magnetic properties associated with this change.